1. Field of the Invention
The present invention relates to an improved electromagnetic wave, particularly microwave, curing apparatus and method of use thereof for continuous processing of a material, In particular the present invention relates to an apparatus which prevents leakage of microwaves from the cavity used for the processing.
2. Description of Related Art
The prior art has described various apparatus for continuous processing of materials using microwaves. In each instance spaced metallic projections are mounted adjacent the material being processed without touching it so that there is minimal leakage from the space between the material and the projections. Nevertheless, there is leakage. Illustrative are U.S. Pat. Nos. 2,627,571 to Hiehle et al, 4,253,005 to Gordon et al, 4,227,063 to Edgar et al, 4,477,707 to Kim, 4,488,027 to Dudley et al, 4,559,095 to Babbin, 4,570,045 to Jeppson, 4,861,955 to Shen, 4,906,309 to Bichot et al, 4,999,469 to Dudley et al and 5,217,656 to Buckley et al. These patents only deal with microwave leakage from a cavity in a continuous processing of non-conductive materials. Wei et al described microwave processing of composites at an AICHE meeting in 1990, in SAMPE Journal pages 33 to 38 (1991) in Proceeding of ICCM/VIII 1, 10-L (1991) and in ANTEC '92 Conf. Proc. 1170 (1992). Microwave curing of composites is also described in Lee et al, J. of Composite Materials 18, 387-409 (1984); Ippen, J., Rubber Chem. Technol. 44, 294 (1971); Loos, A. C., et al., J. Composite Mat. 17, 135-169 (1983) and Wang, C. S., Rubber Division, American Chemical Society, 134-145 (1983). The problem is that there is no microwave apparatus available for continuous processing of conductive materials.